Method for Determining Active Communication Sessions and Communication Session Information Server

1. An apparatus comprising: a memory; and a processor coupled to the memory to execute: a challenge unit to: receive a request to identify active Push-to-Talk over Cellular telecommunication conference sessions of a first and a second communication session server from a plurality of communication session servers, wherein the first session server and the second session server each control a corresponding Push-to-Talk over Cellular telecommunication conference session; transmit, in response to the request, challenges to the first session server and the second session server; receive, based on the challenges, challenge responses from the first and second servers, wherein the challenge responses include an indication of an activity status of the corresponding Push-to-Talk over Cellular telecommunication conference session; and a response unit coupled with the challenge unit, the response unit to: generate a single response that includes the indication of the activity status of the corresponding Push-to-Talk over Cellular telecommunication conference session from the first session server and the second session server; and transmit the single response.

2. The apparatus of claim 1 , wherein the challenge unit is to transmit the challenges based on a received request from a communication session participant appliance, and the response unit is to transmit the single response to the communication session participant appliance.

3. The apparatus of claim 1 , wherein the processor is further to execute a condition checking unit coupled with the response unit, the condition checking unit to: identify a condition of an active communication session; and identify, based on the respective challenge responses, active communication sessions that fulfill the condition; and the response unit is further to generate the single response based on the activity statuses of communication sessions that fulfill the condition and inactive communication sessions, and the signal response not based on activity statuses of active communication sessions that do not fulfill the condition.

4. The apparatus of claim 3 , wherein the condition relates to a presence information item or a location information item.

5. The apparatus of claim 1 , wherein the single response is a first single response, and where the challenge unit is further to receive an updated indication from a session server that an active communication session controlled by the session server has become inactive; and the response unit is further to: generate a second single response based on the activity statuses of communication sessions controlled by at least a subset of the plurality of session servers and the updated indication; and transmit the second single response.

6. The apparatus of claim 1 , wherein individual challenge responses include a group address or a participant address for a respective communication session.

7. A method for ascertaining active communication sessions, the method comprising: receiving, at a communication session information server, a request to identify active Push-to-Talk over Cellular telecommunication conference sessions of a first and a second communication session server from a plurality of communication session servers, wherein the first session server and the second session server each control a corresponding Push-to-Talk over Cellular telecommunication conference session; transmitting, from the communication session information server in response to the request, challenges to the first and the second communication session servers; receiving, at the communication session information server and based on the challenges, challenge responses from the first and second communication session servers, wherein the challenge responses include an indication of an activity status of the corresponding Push-to-Talk over cellular telecommunication conference session; consolidating, by the communication session information server, the challenge responses into a single response message that includes the indication of the activity statuses of the corresponding Push-to-Talk over Cellular telecommunication conference sessions from the first and the second communication session servers; and transmitting, from the communication session information server, the single response.

8. The method of claim 7 , wherein the received request is a request from a communication session participant appliance and the single response is sent to the communication session participant appliance.

9. The method of claim 7 , wherein the request includes an indication of a condition, and the single response includes an indication of only active communication sessions that fulfill the condition.

10. The method of claim 9 , wherein the condition relates to a presence information item or a location information item.

11. The method of claim 7 , wherein the single response is a first single response, and further comprising: receiving, by the communication session information server, after the transmitting the single response, an updated indication from a communication session server that an active communication session controlled by the communication session server has become inactive; consolidating, by the communication session information server, the challenge responses of at least a subset of the plurality of session servers and the updated indication into a second single response message; and transmitting, by the communication session information server, the second single response message.

12. The method of claim 7 , wherein an individual challenge response includes a group address or a participant address for a communication session related to the individual challenge response.

13. One or more non-transitory computer-readable media comprising instructions that, when executed by one or more processors of an information server, cause the information server to: receive a request to identify active Push-to-Talk over Cellular telecommunication conference sessions of a first session server and a second session server of a plurality of session servers, wherein the first session server and the second session server each control a corresponding Push-to-Talk over Cellular telecommunication conference session; transmit, in response to the request, challenges to the first and second session servers; based on the challenges, challenge responses from the first and second session servers, wherein the challenge responses include an indication of an activity status of the corresponding Push-to-Talk over Cellular telecommunication conference session; consolidate the respective challenge responses into a single response message that includes the indication of the activity statuses of the corresponding Push-to-Talk over Cellular telecommunication conference session from the first and the second communication session servers; and transmit the single response.

14. The one or more non-transitory computer readable media of claim 13 , wherein the received request is a request from a communication session participant appliance and the single response is sent to the communication session participant appliance.

15. The one or more non-transitory computer readable media of claim 13 , wherein the request includes an indication of a condition, and the single response includes an indication of only active communication sessions that fulfill the condition and inactive communication sessions.

16. The one or more non-transitory computer readable media of claim 15 , wherein the condition relates to a presence information item or a location information item.

17. The one or more non-transitory computer readable media of claim 13 , wherein the single response is a first single response, and further comprising instructions to: identify, after transmitting the first single response, an updated indication from a session server that an active communication session of the session server has become inactive; aggregate the challenge responses and the updated indication into a second single response message based on activity statuses of communication sessions controlled by at least a subset of the plurality of session servers; and transmit the second single response message.

18. The one or more non-transitory computer readable media of claim 13 , wherein an individual challenge response includes a group address or a participant address for a communication session.